Metal casting is a manufacturing process that involves pouring molten metal into a mould to create a 3D metal part. The mould contains a hollow cavity of a desired geometrical shape, and the molten metal is allowed to cool down to form a solidified part.
The term ‘casting’ also refers to the part made by the casting process, which dates back 6000 years. Historically it is used to make complex and large parts, which would have been difficult or expensive to manufacture using other manufacturing processes.
Primarily, casting produces ingots and shapes. An ingot is a casting produced into a simple shape intended for further processing, such as metal extrusion and forging. Shape casting is for near or net shape castings to produce complex geometries closer to the final part.
Types of Metal Casting
Metal casting falls into two groups by the fundamental nature of the mould design. i.e. expendable mould and permanent mould castings. It can be further subdivided into groups depending on its pattern material.
- Expendable mould
- Permanent mould
- Composite mould
Before choosing a suitable metal casting for a given engineering product design, consider the following factors.
- Part shape and size
- Required quantity
- Required tolerance
- Material
Expendable mould casting
Expendable mould casting uses a temporary non-reusable mould to produce the final casting as the foundry breaks the mould to get the casting out. Sand, clay, and plaster are common materials used to make these moulds. To improve the qualities of disposable moulds, binders known as bonding agents are typically used. Expendable mould casting can be used to cast complex, sophisticated shapes.
Read more: What is Metal Casting?